1. Field of the Invention
The present invention relates to an antifungal phyllosilicate having excellent water resistance, chemical resistance, heat resistance, prolonged antifungal property and weather resistance. The antifungal phyllosilicate of the invention is useful as an antifungal agent which can be incorporated into a molding material such as resins (e.g., rubber and plastics) or which can be coated onto the surface of a molded article to impart an antifungal property to the molding material or the molded article. The present antifungal phyllosilicate can also be blended with an inorganic antibacterial agent to provide an antibacterial and antifungal composition excellent in water resistance, chemical resistance, heat resistance, a prolonged antifungal property and an antibacterial property, particularly excellent in an antifungal property by which the germination of spores of fungi can be inhibited.
2. Description of Prior Art
Up to date, various types of organic and inorganic antibacterial and antifungal agents have been developed for imparting an antifungal property to a desired material.
As the organic antibacterial and antifungal agents, there have been known quaternary ammonium compounds such as benzalkonium chloride; sulfur-containing benzimidazole compounds such as 2,4-thiazolylbenzimidazole; bisthiocyanate compounds such as methylene bisthiocyanate; quinolinol compounds such as 8-quinolinol; alcohols such as ethanol; aldehyde compounds such as formalin; phenol compounds such as cresol; carboxylic acid compounds such as sorbic acid; and so on.
As the inorganic antibacterial and antifungal agents, there have been known those comprising an antibacterial metal ion, such as silver ion, copper ion and zinc ion, carried in a material such as active carbon, apatite and zeolite.
However, the conventional organic and inorganic antibacterial and antifungal agents have some disadvantages to be improved.
For example, the conventional organic antibacterial and antifungal agents are generally poor in heat resistance. Therefore, when incorporated into plastics or fibers under heating, they tend to cause discoloration or blowing of the resultant products or tend to be evaporated or degraded during the incorporation and, as a result, a satisfactory antibacterial or antifungal effect of the agents can not be achieved. In addition, the organic antibacterial and antifungal agents are also poor in chemical resistance and show a relatively high solubility to any solvent. Therefore, when used with a solvent for molding an article, they tend to be leached out from the resultant article, which causes the decrease in antibacterial or antifungal effect of the agents and gives some fear of adverse influence to a human body. For these reasons, the organic antibacterial and antifungal agents are limited in their practical applications.
On the other hand, although the conventional inorganic antifungal agents are excellent in heat resistance and chemical resistance, they exhibit a poorer antifungal effect relative to the antibacterial effect.
For the purpose of improving the above-mentioned disadvantages of the conventional antibacterial and antifungal agents, there has been proposed an antibacterial and antifungal phyllosilicate obtained by substituting at least a part of ion-exchangeable metal ions of a phyllosilicate by an antibacterial and antifungal organic compound (see Japanese Patent Application Laid-open No. 4-292410).
However, the present inventors have found that the phyllosilicate obtained by the above-mentioned technique has some disadvantages such as discoloration and poor weather resistance, and that the organic compound present in the phyllosilicate causes such disadvantages.